Apparatus for perforating hollow articles



Feb. 19, 1957 A. E. coMsTocK APPARATUS FOR PERFORATING HOLLOW ARTICLES Filed July 16, 1952 4 Sheets-Sheet 1 IN V EN TOR.

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APPARATUS FOR PERFORATING HOLLOW ARTICLES Filed July 16. 1952 4 She'ets -Sheet 3 1957 A. E. coMsTocK APPARATUS FOR PERFORATING HOLLOW ARTICLES Filed July 16, 1952 4 SheetsSheet 4 w -1 A H h Q Q H G H H Q w H H 6 BY I I nite L States Patent A 2,781,843 Patented Feb. 19, 1 957 ice APPARATUS FoR PERFORATlN G HOLLOW ARTICLES Alfred E. Coin'stock, Palmer, Mass., assignor, by mesne assignments, to The Diamond Match Company, New York, N. Y., a corporation of Delaware Application July 16,1952, Serial No. 299,214

Claims. (Cl. 164*51) This present invention relates to an improved apparatus and, components thereof for perforating special articles, particularly of paper pulp construction such as a molded pulp egg carton. The cartons are normally molded to provide two or more integrally hinged, hollow sections, at least one of which is cellular in nature and receives eggs or other articles. These sections are folded about the connecting hinge thereof into a closed, article receiving and protecting relationship. The invention primarily deals with apparatus for cutting or slitting and perforating a carton of this type transversely at its midpoint so as to render the same readily divisible manually by tearing along the weakened perforated line.

The preparation of a special molded article of this type presents certain problems when it is borne in mind that it is advantageous to perform the perforating operation following molding and drying of the carton, rather than at the time of molding, as by appropriate provisions in the molding die. Since cartons of this type are widely marketed in both the divisible and non-divisible style, it is desirable to produce both styles on the same die equipment. This avoids the tying up of a given molding machine to production of the divisible style only, or the loss of time incident to a change over of dies to produce that style, and not the non-divisible.

The difficulty arises in part from the nature of the treatment to which the carton is to be subjected, and its desired physical attributes to conform thereto. Firstly, the car ton must have adequate rigidity coupled with tear and twist-resistance to withstand normal handling in packing,

crating, shipping, stacking and storage; yet it must be readily rupturable by a clerk or housewife .to subdivide the same, as intended. This in itself is a hard order to fill.

Second, the shape of the carton and its constituent material do not lend themselves to successful and practical slitting and perforating, by existing types of cutting or perforating devices, at the various angularly related carton surfaces, except possibly by involved, compoundacting cutting and perforating equipment, expensive and slow acting in operation.

Thirdly, even equipment of the last named sort with which I am familiar is not designed to produce the composite slit-perforation type of weakening of a specially shaped hollow molded pulp carton, such as the present equipment operates on, with the objective of balancing the factors contributing both to carton strength and carto" weakness or rupturability, as discussed above.

It is therefore a general object of the invention to provide an improved article cutting or perforating apparatus having provisions for automatically advancing molded pulp cartons, or other equivalent articles, preferably with the articles arranged in laterally aligned sets, into the zone of operation of a special reeiprocatory cutting-perforating instrumentality; for automatically engaging, supporting and clamping the article or articles against distortion; for performing a one-stroke cutting-perforating operation on the thus sustained articles, in which a composite line of 2 slits and. perforations is produced across the width of each of the cartons being operated on; and for th'e'reafter'releasing the cartons from their supporting provisions and conveying the same away from the perforating and cutting zone; r r

Another general object is to provide the slitting-perforating knife assembly of special character for use in the apparatus described inthe preceding paragraph.

More specifically, it is an object to provide, in association-with means for suitably feeding, supporting anddischarging a carton'in relation to an operating'zone, an improved cutting assemblyof edge-sharpened slittingand perforating knives or special configuration, individually and removably mounted on a cutter head, the shaping,

' sharpening and positioning of the knives being particularly devised in relation to the outline of the carton or other article to be operated on whereby a composite type of slivperforated, article weakening line is formed to extend across the article at an interior zone.

Another object is to provide apparatus, or a cutting assembly therefor, as described in the preceding para graph, in which the cuts produced by the'assernbly are so distributed along the weakening line and are so related to the shape of the carton that surfaces of the latter which are not of cardinal importance, in the matter of its rigidity arid resistance to fiexure and torsion, are-inore extensively cut by slits than other portions having primary importance in these matters, all to the end that the resulting carton can ultimately be severed by the user with reasonable ease and convenience, yet maintain desired strength prior to such severance to stand the sort of treatment to which it is normally subjected in use.

Yet another object is to provide a cutting and perforating knife assembly, as referred to, in combination with an article supporting and clamping unit comprising male and female forms or dies shaped in conformity with the cross sectional outline of the article operated on, this unit coacting with slitting and perforating knives ofthe assembly to obtain a controlled slit-perforating operation without excessive excising likely to objectiom ably decrease the strength of the article.

The foregoing statements are indicative in a general way of the nature of the invention. Other objects will be apparent to those skilled in the art upon a full understanding of the construction and operation of the apparatus.

A single embodiment of the invention is presented herein for purpose of illustration, and it will be appreciated that the invention may be incorporated in other modified forms coming equally within the scope of the appended claims.

In the drawings:

Fig. l' is a fragmentary view of the improved apparatus in end elevation; i

Fig. 2 is a front elevational view of the apparatus, partially broken away to illustrate the arrangement or relationship of its article guiding, itsarticle sustaining and its opera-ting means, as well as provisions to support and to actuate the same; t

Fig. 3 is .a fragmentary view of more or less schematic character, in vertical longitudinal section along a line corresponding toline 3'-3 of Fig. 2,- more clearly illus trating the structure and relationship of article feed and control means, article supporting means, slitting-perforating head and so on;

Fig.- 4 is a fragmentary top plan view illustrating a type of molded pu egg car on an which the present apparatus has operated to convert the sarne. to a divisible t pe, the carton being shown in the relatively flat, completely opencondition in which it is delivered from a drying press, prior to slit-perforating the same;

Fig. 5 is a fragmentary perspective view of the same carton in a closed condition;

Fig. 6 is a view in front elevation of the improved slitting-perforating knife assembly adapted to be mounted on a reciprocable head of the apparatus; and

Fig. 7 is an end view of the knife assembly of Fig. 6.

A proper understanding of the purpose and functioning of the present improvements can best be had by a preliminary understanding of the nature of the molded pulp article which is intended to be converted to a divisible or weakened condition by those improvements. While other types of articles may be operated on, a molded pulp carton, best shown in Figs. 4 and 5, is admirably suited to illustrate these matters. Accordingly, with reference to Figs. 4 and 5, a carton C is shown which is of the general construction illustrated and described in the patent to Cox No. 2,529,140 of November 7, 1950, entitled Carton. It has three main constituent parts, namely a cellular, egg receiving bottom section a; an open, traylike cover, section b, integrally hinged to the bottom section by a molded crease construction 0, which crease is of substantial width at certain points along its length; and an internal cover bracing flap or flange d, which is hinged to the opposite side margin of bottom section a by a crease e generally corresponding to crease c.

Scalloped egg accommodating recesses f are formed along the side walls of cover section c; these are in transverse alignment with egg receiving cells g in bottom section a and serve to increase the egg receiving space in the cover. Similar scalloped formations h are provided in the reinforcing flange (1. Bottom section a is molded to provide a series of longitudinally spaced center posts i along its longitudinal center line, with longitudinal partition elements j and transverse partition elements k connecting these posts lengthwise and crosswise. The partition elements merge upwardly into the outer corners of posts i and coact with the latter in defining the cells g. The partition elements similarly merge with supporting and cell defining abutments l at the sides and ends of section a, with which flange d and cover section b vertically engage in the closed condition of the carton, illustrated in Fig. 5 of the drawings. Engagement is bad at the inwardly extending abutment webs m of the cover section which intervene between the scallops 1 adjacent hinge c, and of the flange d.

A transversely extending, slitted and perforated line of subdivision is generally designated by the reference character L; the particular arrangement of component slits and perforation of the line L bears on structural details of the improved cutting and perforating structure which is the subject matter of this invention, hence is worthy of note in some detail.

Viewing cover section a of the carton shown open in Fig. 4 and closed in Fig. 5, it is desirable that its extreme outer margin or free edge (at the top of Fig. 4) be uninterrupted and uncut throughout its length, i. e., that substantial material be left between this edge and the com- "mencement of the slitted-perforated line L. This affords adequate strength to resist initiation of accidental tearing, as would be encouraged were the line L continued to intersect the free margin of the cover. Accordingly, a perforation n is formed in the central abutment. The perforation does not extend all the way inwardly to the corner of the abutment m; it is desired to maintain a degree of rigidity at the shoulder of the latter.

Proceeding downwardly, the line L includes a slit of substantial length (see Fig. which extends practically the entire vertical height of the adjacent front wall of cover section b, terminating short of the junction of the wall with the top forming panel p of the section. A certain amount of strength and resistance to accidental tear is also desired to be retained at this natural strong point of the cover, i. e., at its edge corner.

Next, line L comprises a transversely extending series of uniformly spaced perforations q which terminate just 4 short of the opposite cover corner. An elongated slit 1' follows similar to slit 0, being of length practically coextensive with that of the wall in which it is formed. Then a somewhat elongated slit s extends across a wide portion of the hinge crease c to overcome the considerable natural rigidity of this formation.

Lines of short perforations I extend along each of the transverse, cell dividing partitions k, and an intermediate, relatively elongated slit u is disposed transversely across the centermost cell dividing post i. Slitperforated line L ends with a slit v severing the flangebottom section hinge crease e and a terminal series of perforations w ending short of the free edge of flange (I.

A subdividing weakened line L of the foregoing character has the advantage that it best conserves the original strength, rigidity and ability of the molded pulp carton to resist crushing, twisting or tearing stresses on the closed carton, While aifording manual rupturability.

However, by the same token, its special nature imposes a problem in the conversion of the finished carton for subdivisibility. It cannot be formed by existing non-compound or single acting types of cutters, due to the angular relationship of the various surfaces of the carton in its flat, open condition (Fig. 4). That is, it is impossible to make a series of perforations such as the cover perforatrons q and at the same time make a simultaneous cut on an angularly related surface, such as the slits 0 in the cover walls. Furthermore, the inherent relatively weak, readily tearable characteristic of molded paper makes it impractical to form therein a perforation-like slit of substantial length using ordinary punching procedures.

I have discovered it to be preferable that shearing action be resorted to in forming all of the various sorts of cuts in line L, in the interest of avoiding tearing. Accordingly, the apparatus illustrated in Figs. 1, 2 and 3 has been devised with this in mind, and embodies improvements in the cutting unit, best illustrated in Figs. 6 and 7, to cope with problems occasioned by the special nature of the article operated on. A general description of the apparatus as a whole logically precedes a consideration of the cutter unit illustrated in the last named two figures. Accordingly, reference should now be made to Figs. l, 2 and 3 of the drawings.

The apparatus comprises a pair of laterally spaced upright standards 10 each appropriately supported on an angle iron base 11. Provision is made in the lower portion of each of these standards to journal a transversely extending drive shaft 12, which carries similar cams 13 inside each of the respective standards, the cams being fixed to the shaft. Cam follower rollers 14 ride on the respective cams 13, the followers being carried by vertically extending slide members 15 which are appropriately guided for up and down sliding action on the standards by well known provisions not necessary to describe in detail. Each slide is provided with a laterally extending shoulder plate 16adjacent its upper end, and a pair of horizontally extending platen supporting beams 17 are bolted to plates 16 (Figs. 2 and 3).

Beams 17 are bridged by a transversely spaced series of male die platens 18, fixedly secured to the beams to constitute a form or die supporting structure of inverted U-shaped outline. A block-like male carton sustaining form or die 19, which will be hereinafter referred to in greater detail, is removably secured in any suitable fashion, permitting different setsof dies to be appropriately interchanged when cartons C of different sectional outlines are operated on by the apparatus.

A number of transversely spaced dies 19 are carried by the cross beam structure, it being the function of these dies to enter into the interior of and support cartons C which advance along parallel carton guide chutes 20, arranged at a right angle to the beam structure and in vertically elevated relation thereto. Chutes 20 are appropriately supported on standards 10, as by transverse channel brackets 21 secured to the standards. Each chute guide may be constitutedby a pair of opposed, elongated angle irons 22 arranged in transversely spaced relationship, as illustrated in Fig. 2, with horizontal flanges thereoffacing one another. Chute supporting brackets 21 may also serve tosupport the upper reach '23 of an endless traveling belt conveyor 24 (Fig. 3), said upper reach being arranged coplanar with and between the horizontally disposed flanges of chute elements 22. The spec ing of these elements is such as to maintain a longitudinal series of cartons C improper alignment asthey are advanced by belt reach 23 transversely of the vertical zoneof operation of the apparatus.

Referring to Fig. 3, conveyor belt 24 is trained about sets of vertically and horizontally spaced pulleys 25 certain'of which are continuously driven by a well known means not deemed necessary to further illustrate or describe. Two sets of intermediate pulleys, specially designated 25, are arranged to by-pass upper belt reach 23 downwardly in the zone of vertical reciprocation of the dies 19 and coacting instrumentalities (to be described), the cartons C being supported in this zone, prior to engagement of the dies therewith, by the guide chutes 20. These are longitudinally interrupted in the zone'of operation to give clearance for vertical movement of the instrumentalities, but the ends of the chutes at the interrupted zone are still close enough together to support the cartons.

A suitable simple escapement device, generally designated 26 is arranged on standards to interrupt longitudinal travel of cartons C on conveyor 24 in the zone of operation of the improved cutting unit of the invention, which is for convenience generally designated by the reference numeral 27. This device may consist of a U-shaped carton halting arm 28, having rearwardly extending side pieces 29 connecting the ends of a cross piece 30. The side pieces are appropriately pivoted to a bracket 31 on the frame. An operating crank 32 is se; cured to escapernent arm 28 at the pivot thereof and is intermittently actuated through an elongated link 33 by any suitable intermittent drive means,'such"as'an opcrating part of a carton drying unit with which'the pre's ent apparatus is intended to be associated. Cartons C are intermittently restrained at the operating zone-by the; cross piece 31) as the 'latter'is' intermittently operated between the solid and dotted line positions illustrated in Fig. 3, the driven belt reach 23 meanwhile sliding beneath the halted cartons. I Y v I Slitting and perforating assembly 27 is Vertically reciprocated in timed relation to the vertically reciprocator'y movement of male d-ies orforrns 19. Its drive, like that of dieplaten beams 17, is derived from main shaft 12. To this end, the shaft 12 has-eccentrics 35 fixedly secured to each of its opposite ends, externally of the respective standards 10, as shown in Figs. 1 and 2. Eccentric straps 35 surround the eccentrics and adjustably receive the vertically extending pitman connecting rods 37. The upper ends of rods 37 are pivotally mounted by suitable plates 38 to slide block'trunnions 39 which are appropriately guided for vertical sliding movement in the upper portions of the machine standards 10. These upper portions of standards it) are rigidly connected and held in transversely spaced relation by means of a'pair of elongated, transversely. extending, front and rear cross ties 40", and end spacers 41 are fixedly'secur'ed to oppositeends of the ties. Guide bushing mounting plates 42' are spaced transversely from one anotheralon'g' the length of cross ties 40 and are fixedly secured to bridge the space between the latter, at a right angle thereto.

The slide block trunnions 39 are bolted to opposite ends of a pair of parallel cross beams 45 each of which has a transversely extending, horizontal cutter mounting plate 46 bolted to the lower edge thereof. These beam members are thus reciprocated together as an el'on gated, transversely extending, cutting head, gener'aIIydes ignatcd 47 for convenience; on which perforating and gangsta cutting-assemblies 27 are 'rriedier pnetationen carton C thehead being'v'er'tically reei roeaiea by pinnan rods 37, "in timed relation to the opposite reciprocation of the male die platen beam structure by cams 13, when shaft 12 is unidirectionally rotated. Any appropriate source of power (not shown) may be applied to the shaft. I

The slitter'g'perforator mounting plates 46 which are secured .to cross beams support a plurality of the perf'orator-slitter assemblies specially illustrated in Figs. 6 and 7 of the drawings. Each of these assemblies, as devised for treatment of the carton C chosen for illus- ,tr'ation, comprises an aligned, coplanar set of flat knife blades 48, 49, 50, 51, 52, 53 and 54. The number may be increased or decreased and the order of end-series arrangement of the knives may be changed, depending upon the characteristic of the object to be conditioned. Individual changes may also be made with reference to the shape of the cutting edges of these knife'members, as will he better understood as the description proceeds.

Eachblade is 'releasably clamped adjacent its upper edge between apair of knife holders 55 of L-shaped cross section, by means of set screws 56. Similar set screws may be employed to releasably secure the blade holders to the upper surface of the respective mounting plates 46, which are spaced sufficiently from one another to enable the blade todepend therebetween (Fig. 3)., :For convenience the assembly of knife blades 4854 will hereinafter be referred to'generally by the reference numeral 57.

Blade assembly 57 also depends between the two like sections of a female carton sustaining form or die 58, as illustrated in Fig. 3, which die is fixedly secured to and beneath a floating support plate therefor, designated 59.

' thereby guiding the female die sections for floating movement with relation to the eccentric-actuated beam structure 27. Coil compression springs 62 normally maintain die support plate 59 in downwardly spaced relation to the blade assembly mounting plate 46.

Male and female carton sustaining dies 19, 58, respectively, are complementarit shaped in cross section, in conformity with the cross sectional outline .of that portion of carton C which adjoins either side of its center, across whichthe line of slits and perforations L are to be formed. Each is adapted to nestingly engage an opposite side of a carton, across the cells g of its bottom section a aswell as across its noncellular cover b. It is seen that it is only necessary to so sustain the carton in a zone adjoining the intended line L which is of two-cell width (Fig. 3).

Referring again to Figs. 6 and 7, thecarton C is illustrated in dot-dash line in the flat, opened out condition in which it is engaged by dies 19, 58 (not shown in Figs. 6 and 7) and thus rigidly supported to be operated on by the blade assembly 57. The blades'48'54 are shown in solid line in a relatively elevated position relative to carton C, just before taking slitting and perforating engagement with the latter; they'are shown in dotted line following full downward stroke of assembly 57.

In the last named position the left hand end cutting blade 48 slices downwardly through the outer wall of cover section b, producing the somewhat elongated slit 0 in the latter (see Fig; 5 of the drawings) and ends up with its sharpened and pointed tip perforating the abutment'ledge or web in at the intermediate cut n. Blade 50 similarly slits the opposite wall of the cover head at r and, its tip seversfthe' covferhinge c at s. Simultaneously, the second intermediate blade 49' engages top" panel p of 7 the cover section and its sharply serrated lower edge slices the series of short perforations q.

Blades 51 and 53, by reason of the irregular, specially shaped serrated outline of the sharpened cutting edge thereof, produce the perforations tin the transverse carton partition k, while intervening V-cdge blade 52 produces a slit cut it of substantial length in the central separating post i of cellular bottom section a. The endmost blade 54 operates on flange hinge e of the carton and on the flange 11 itself, producing the hinge-severing slit v and the series of flange perforations w, respectively.

it is seen that a series of knife edged blades is rendered capable, in a unidirectional stroke, of producing the requisite linear, arrangement of slits and perforations, of differing length and order, in the various steeply angled surfaces of the special article illustrated. The cuts are made by slicing shear, i. e., progressively along the surfaces so that the fibers are not subjected to destructive load such as would weaken the stock in the area surrounding the cuts. Certain of the blades (48, 50 and 54, for example) make cuts of different character, namely a perforation or series of perforations combined with an elongated slit. The blades are readily removable individually from the mounting plates 46 for replacement or sharpening, or to modify the arrangement or distribution thereof, as dictated by the shape of the particular article being slit-perforated.

in the operation of the apparatus as a whole, cartons C are continuously advanced on the upper reach 23 of belt conveyor 24 until halted by intermittently operating escapement device 28. In this position the male dies 19 are cam elevated on platen beam 17 into engagement with the carton of a row at the operating station, elevating the cartons to some slight extent above guide chute 20. The knife supporting beams 45 and plates 46 are simultaneously shifted downwardly by eccentrics 35 and connecting linkage, the downward throw thereof being sub.- stantially greater than the upward throw of the cam 13 and connecting instrumentalities.

As the cutting head 47 descends, female die sections 58 engage over the carton, clamping the same to the male dies 19, but under a yielding pressure due to the floating nature of die support plates 59. As the beams 45 continue to descend, knife assembly 57 is thrust downwardly throughthe space between the sections of the respective male and female dies 19, 58. Its constituent blades 4854 slit and perforate theintended line L in cartons C, as previously described. The two reciprocatory members then separate, allowing the carton to rest on the guide 20, and upon elevation of escapement arm 28 to dotted line position by the link 33,.the conveyor belts 24 again assume control of the cartons. They travel outwardly away from the operating zone, making way for another set of cartons to be operated on.

I claim:

1. slitting-perforating apparatus comprising aseries ,of flat blades arranged in side edge abutting, coplanar relation as a blade assembly, said assembly being mounted for movement as a unit toward and from a hollow, nonplanar molded pulp article to be slit-perforated, said blades being disposed with the cutting surfaces thereof in a non-aligned arrangement which is in approximate conformity with surfaces of the article to be slit-perforated by said blade assembly, means to move said assembly into and out of cutting position, the cutting surface of certain of said blades being provided with serrated cutting edges sharpened to slice a line of perforations in a surface of said molded pulp article extending normal to the plane of cutting movement of the blade, the cutting surface of other of said blades having convergent cutting edges sharpened to slice a slit through a surface of the article extending at an abrupt angle to said perforated surface, an article engaging die defined by angularly related surfaces and conforming in shape to the outline of said article and blade assembly, means yield-ably supporting said die for movement with said blade assembly and immediately adjacent the same into nested and sustaining relation to said article, a further article engaging die shaped in conformity with the outline of the article and complementary to the outline of the first die, means to move said last named die oppositely of the direction of movement of said first named die and said blade assembly into nested and sustaining engagement with the opposite surface of the article.

2. Apparatus for operating on a hollow article characterized by horizontal surfaces and upstanding surfaces serving to define a hollow article interior, comprising an operating head, means to reciprocate said head vertically for engagement with said article, a shaped article sustaining die engageable with a surface of said article engaged by said operating head, means yi'eldably supporting said die on said head for relative movement of the head and die following sustaining engagement of the latter with an article, a further article sustaining die, means actuating said further die in timed relation with and for movement oppositely of said operating head into sustaining engagement with an opposite surface of said article, means sustaining spaced sides of said article from beneath at an operating station located between said head and said further die and in the paths of opposite movement thereof, and an endless, continuously moving conveyor belt transporting successive articles past said operating station, said conveyor belt being by-passed vertically around said operating station to afford clearance for vertical die movement.

3. slitting-perforating apparatus comprising a series of flat blades arranged in side edge abutting, coplanar relation as a blade assembly, said blade assembly being mounted for movement as a unit toward and from a hollow, non-planar molded pulp article to be slit-perforated, said blades being disposed with the cutting edges thereof in a non-aligned arrangement which is in approximate conformity with surfaces of the article to be slit-perforated by said blade assembly, certain of said blades being provided with serrated cutting edges sharpened to slice a line of perforations in a surface of said molded pulp article extending normal to the plane of cutting movement of the blade, another of said blades having convergent cutting edges sharpened to slice a slit through a surface of the article extending at an abrupt angle to said perforated surface, individual supports for said blades comprising clamping elements engaging opposite faces of the blades, means to releasably secure said blades to said elements, a support sustainingly engaged by said elements to hold the blades in said coplanar relationship, an article engaging die defined by angularly related surfaces and conforming in shape to the outline of said article and the cutting edges of said blade assembly, means yieldably supporting said die for movement with said blade assembly into nested and sustaining relation to said article, a further article engaging die shaped in conformity with the outline of the article and complementary to the outline of the first named die, means to move said second named die in timed relation with and oppositely of the direction of movement of said first named die and said blade assembly into nested .and sustaining engagement with the opposite surface of the article, means at an operating station located between said article engaging dies and in the path of movement thereof for sustaining spaced slides of said article and means for transporting successive articles past said operating station.

4. Apparatus for slit-perforating on a line extending across a molded pulp carton which carton is characterized by horizontal wall surfaces and upstanding wall surfaces defining therewith a hollow article accommodating interior, said apparatus comprising a reciprocating head, means to support said head for vertical reciprocating movement toward and from said carton, a shaped die .engageable with a surface of said carton, means yieldably supporting said die on said head for relative movement of the head and die following wall sustaining engagement of said die with the carton, a further shaped die, means mounting said further die for movement in timed relation with and oppositely of said head into wall sustaining engagement with an opposite surface of said carton, means supporting spaced side portions of said carton from beneath at an operating station located between said head and said further die and in the paths of movement thereof, and an endless conveyor for transporting successive cartons past said operating station, said conveyor being by-passed vertically around said operating station to afford clearance for vertical die movement.

5. Apparatus for slit-perforating on a line extending across a molded pulp car-ton which carton is characterized by horizontal wall surfaces and upstanding Wall surfaces defining therewith a hollow article accommodating interior, said apparatus comprising a reciprocating head, means to support said head for vertical reciprocating movement toward and from said carton, a shaped die engageable with a surface of said carton, means yieldably supporting said die on said head for relative movement of the head and die following wall sustaining en' gagement of said die with the carton, a further shaped die, means mounting said further die for movement in timed relation with and oppositely of said head into wall sustaining engagement with an opposite surface of said carton, means supporting spaced side portions of said oar-ton from beneath :at an operating station located between said head and said further die and in the paths of movement thereof, and a traveling conveyor for transporting successive cartons past said operating station, said conveyor being arranged to afford clearance at said operating station for vertical die movement.

Reierences Cited in the file of this patent UNITED STATES PATENTS 21,657 David Oct. 5, 1858 1,625,748 Schiess Apr. 19, 1927 2,038,857 Rutter Apr. 28, 1936 2,203,884 Stone June 11, 1940 FOREIGN PATENTS 21,961 Great Britain Oct. 9, 1902 26,596 Great Britain Nov. 19, 1913 649,942 Germany Sept. 7, 1937 551,569 Great Britain Mar. 1, 1943 

